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It's in part a cycle -- land to humans to waste to land. Only in part as nitrogen can oxidize to go back to the air, so it needs to get fixed again by bacteria.

Actually, you excrete most of your nitrogen through kidneys. Pig/human dung contains just 0.3% of nitrogen by weight. Anyway, you can read historical data - human waste is not enough, even using it for compost required to lay fields fallow one year out of three or four (depending on location).

That's because the total amount of fertilizers used is huge. Very little of it is lost, but even that can cause trouble.

What that shows is that alternatives have worked. China is one of the most densely populated places on the planet. If they could do it, it shows the US could do it and other countries could do it.

It was not nearly the most densely populated place (England was) before the 20-th century. China was pretty average compared to European countries.

Still, you can't compare what you presumably had to do with limited tools and limited materials and limited information in a (probably) limited climate on impoverished soils with what is really possible with good tools, abundant materials, abundant information, in a good climate on well prepared soils.

We had lots of information, good enough manual tools and adequate soil. It still takes A LOT of labor if pesticides are not used. Real industrial farming is way more economic and might actually be _healthier_ for the environment, because pesticides allow no-till agriculture.

I see. I'll try not to assume that context might explain a lot.:-) Still, at the very least, it may be something like how someone who works with Microsoft products a lot might never think that open source software is possible or even better sometimes? Have you studied organic agriculture? Have you read Widdowson's book?

I certainly studied the organic farming including the 'Holistic' book. It's pretty much the same story as alternative medicine vs. actual medicine - the parts of alternative medicine that work simply become medicine. I've also studied the opposite opinions that pure organic farming is not sustainable and so far it definitely looks like it.

For example, while humans don't fix nitrogen, human waste contains a lot of nitrogen from food that is eaten.

:facepalm: And where does nitrogen in food come from?

Considering how much fertilizer is wasted in modern systems, you can see that this was a big deal in China as part of a closed cycle including other techniques to restore soil fertility.

Very little fertilizer is lost in modern agriculture in relative terms.

Granted there are other issues with pathogens and contamination from "night soil", but nonetheless

Pathogens are not a problem, they are outcompeted by soil bacteria during composting.

China is an example of doing wihout the Haber process for 4000 years and still supporting big populations by other means.

facepalm^2. China's population grew 3 _times_ during the last century virtually without increasing the land use, because of the fertilizers and pesticides.

If we wanted to do rotational cropping and intercropping to just feed humans, it seems to me it is likely quite feasible, especially with agricultural robots to manage that complexity instead of a lot of manual labor.

Still won't work. You'll need livestock for manure (to concentrate nitrogen and other nutrients). And agricultural robots are a pipe dream. Unlike you, I actually helped to grow my own food (lean years after the USSR collapse) so I appreciate the amount labor required for that.

And I also worked with the Great Evil (Monsanto) on actual modern agriculture to appreciate the difference.

Duh. So perhaps these billions of people should eat tree bark instead of wheat, rice and corn? Fruit trees are _easy_ - they grow slowly and don't require much fertilizer anyway.

And with most vegetables you have the same problem - if they are high-yield and annual then you need fertilizer. Even beans (that can fix their own nitrogen) produce less yield in dry weight than wheat with fertilizer.

Also: bushles? In what age do you live? What is a bushel?

It's a standard unit for crop yield measurement (1 bushel of wheat is 27 kg) in the US. It's stupid but traditional, kinda like hydrologists use acre-feet for water storage data.

Wow! 1909 is so modern. Not. Since that time wheat yields were improved by more than 5 times with the help of fertilizers.

Human waste does not help with nitrogen as humans can't _fix_ atmospheric nitrogen. You can use animals to help to _concentrate_ nitrogen from pastures into small fields, but this simply does not scale.

As for 'holding capacity' - that's such a bullshit that only greenie hippies with granola for brains can buy it. In a typical fertilized soil the concentration of nitrogen is usually around 25 parts per _million_ by weight. Meanwhile, potassium is naturally about 100ppm with huge variation (from 40ppm to 130ppm) having little effect on crops. The rest of micronutrients like zinc or iron are even less.

Yeah, sure. Please show me a "permaculture" that provides at least 40 bushels of wheat per acre with the total costs less than $6 per bushel. This is about average performance now, with top cultivars and agricultural techniques allowing to go up to 150 bu/ac yields (but they also have higher costs).

Legumes help, but their nitrogen content is way too low to support non-happy-hippie agriculture where you actually need high yields. It's useful to _decrease_ the dependency on nitrogen fertilizers, but they can't replace them. And slow-release fertilizers are very well used in traditional agriculture.

This very topic is discussed in "Entertaining Physics" printed first in 1912. And I'm sure it has been discussed even earlier.

Mathematically it's an example of a degenerate orbit with one zero semi-axis, and the orbital period can be simply calculated from Kepler's laws.

What's more interesting, it even holds true if you do not move through the center of the Earth! For example, a train from any place on Earth to any other place on Earth will move all by itself and always arrive at destination in about 45 minutes (neglecting the oblateness of the Earth and need to compensate for Coriolis forces and friction) if you put it inside a completely straight tunnel.

Each financial transaction over NFC includes a cryptographic signature. All the attacks on NFC basically involve signal interception and/or retransmission. The next generation of NFC systems will include distance-bounding protocols to combat even that possibility.

I'm was an H-1B and I came to the US for a salary that put me in the top tax bracket. My job description included development of critical medical systems.

H1B is simply an employment visa, that could be used for many purposes. There actually are no other options, even for highly qualified professionals (L1 requires corporate relationships, B1-in-lieu-of-H is extremely rare and Green Card processing takes way too much time).

bobo the hobo (302407) writes "The FreeBSD random number has been discovered to be generating possibly predictable SSH keys and SSL certificates for months. Time to regenerate your keys and certs if using FreeBSD."Link to Original Source

Usually, "epoxy" around the edges of a BGA chip is neither an anti-hacking attempt nor a light-proofing attempt. It's called underfill, and its chief purpose is to increase mechanical strength and make the bond more durable than tiny bare solder balls would be on their own.